Compound door



Jan. 24, '1967 E. MUNK COMPOUND DOOR Filed July 12, 1963 ll llollllllrlllll 1K & QM g F W W D T E A United States Patent 4 Claims. (a.52-309 The present invention relates to a compound door which consistsof a profiled and partly plastic-covered frame or members of such aframe which is molded of a mixture of a comminuted organic fibrousmaterial, for example, wood chips, and a thermosetting binder, of aninner structural part intermediate the side parts of the frame which ispreferably made of the same material as the frame, and of panels of athin sheetlike material which cove-r the opposite sides of the innerstructural part and are glued to this part and also to the frame andmay, if desired, also be coated with sheet plastic.

Although compound doors are known in which the frame of the doorconsists of solid wood, there are no such frames known upon which alayer of sheet plastic is molded. Moreover, it is practically impossibleto mold thermosetting plastics directly upon solid wood. There are alsono solid wood frames known which are profiled in such a manner that thepaneling sheets of the door are sunk into undercut grooves in the framewhich are made, for example, of a dovetailed shape. In most compounddoors with solid wood frames, the paneling sheets are glued to bothsides of the entire outer surfaces of the frame, and if the frame is tobe provided with a recess along the outer edges of the door frame, thiscontinuous recess is milled into the wood frame after the entire doorhas been assembled and glued together. The internal structure of such adoor, for example, in the form of ahoneycomb pasteboard construction isalways separate from the frame and glued to the panel sheets. Since thewood frame of such a compound door is paneled only along its flat outersides, the recessed or unrecessed outer edges of the frame are notcovered and willeven if painted or enameled-not give a uniform opticalappear ance since the different materials of the frame, i.e. the solidwood and the panels, have different technological properties and theedges of these different materials will show through the enamel coating.Such a compound door has the further disadvantage that the recesses andapertures for the lock and keyhole and the hinges cannot be cut into thedoor frame until the door is otherwise completed and finally milled tosize. Finally, the solid wood fr-ameof such a door always works, i.e. itswells and shrinks, resulting in warping of the entire door. Suchwarping is aggravated by the fact that the different parts of the door,i.e. the frame, the interior structure, and the panels, have differentswelling and shrinking properties and work relative to each other. Thisis one particular reason why compound doors of this type ofconstruction, even though originally made quite accurately, will oftenlater close improperly. Furthermore, because of these differentproperties, it often occurs that the interior structure will in thecourse of time become marked on the outer surface of the paneling.Although some of these disadvantages and the constantly prevailingdanger of cracks forming in the solid wood may be reduced to some extentby making the frame of a carefully selected wood which is properly driedand free of knotholes, this renders such a door very expensive.

The principal objects of the present invention are to provide a compounddoor which overcomes all of the above-mentioned disadvantages of theprevious compound doors employing solid wood frames, does not warp, may

be produced more quickly and inexpensively, and has a much better andbetter lasting quality and appearance than the previous compound doors.

These objects are attained according to the invention especially bymolding at least the frame of the door under heat and pressure of amixture of comminuted organic fibrous materials, for example, woodchips, and a thermosetting binder to its final desired size and shape,and by then coating all of the outer visible surfaces of the frameincluding the outer recessed or unrecessed edges thereof with a layer ofplastic or plastic-impregnated sheet material. The size and shape of thedoor according to the invention is therefore exactly predetermined sothat, after its completion, no additional work either manual or bymachines has to be carried out thereon,

regardless of whether the door is to fit flush into the stationarysurrounding frame or whether its edges are to be recessed. The aperturesand recesses for the lock, keyhole, and hinges are preferably moldedinto the frame or they may be cut into the molded door frame before thedoor as such is completed. Since the door frame may be molded to itsfinal size and shape in one operation, this also means that the recessalong its outer edges as well as any grooves, projections, or recessesfor decorative purposes may be formed in the same molding operation.Another feature of the new door frame is that a part of the oppositeouter sides of the frame members is provided with molded-in recesses forreceiving the door panels and that the edges of these recesses may alsoby molding be undercut to any desired crosssectional shape to receivethe edges of the door panels. Such undercut edges of these recesses havethe advantage that, when the door panels are to be glued to the frameand its interior structure, these panels may be sprung into theseundercut recesses and will be gripped thereby in the proper position.The edges of the panels are then preferably beveled to a shape inaccordance with the undercut recesses. This has also the advantage that,if the door panels are also coated with sheet plastic, the danger isavoided that the plastic layers might separate along its edges from thepaneling sheets. Furthermore, due to the undercut-ting, the coated oruncoated panels will be held tightly in the frame independently of thegluing and they may be fitted so tightly into the recesses that novisible seam will appear between the coated parts 6 of the frame and thedoor panels.

The frame may either be molded as one integral body without any jointsor it may be assembled of several mitered parts. Although the interiorstructure of the door may also be molded separately from the frame andthen be secured to the inner sides thereof, it is preferable to mold ittogether with the frame, that is, in the same molding operation. For amass production of doors of different heights or different widths itisalso possible according to the invention to mold the interiorstructure integrally with two opposite frame members, the ends of whichare beveled either by cutting or molding, and then to complete the doorby mitering the two other frame members to the first frame members. Inthis case, the interior door structure is preferably not directlyconnected to the last two frame members, but only subsequently throughthe glued-on paneling sheets. The interior structure of the door isdesigned primarily for the purpose of making the door as light andinexpensive as possible, but also to provide a sufficiently strong baseupon which the door panels may be glued. It is therefore preferably madeof a corrugated, honeycomb, or any other shape which insures that thereare an adequate amount of contact surfaces upon which the door panelsmay be firmly glued in a manner so that the points of connection betweenthe internal door structure and the paneling will not be marked andnoticeable on the outer surfaces of the latter. The pressure which isapplied upon the door panels when they are being glued upon the interiorstructure should therefore not be excessive but in proportion to thenumber and size of the contact surfaces of the interior structure. Thedoor panels whether plain or coated on the outside with sheet plasticmay also be made very economically and of the exact size so as to fitproperly into the undercut recesses in the frame even before they arebeing glued into the frame and the contact surfaces of the interior doorstructure.

A very important feature of the compound door according to the inventionis that, whereas in plastic-coated doors with wood frames of priordesigns those parts of the doors which are especially subjected tostresses, namely, either all of the visible parts of the frame or atleast the edge portions thereof are not plastic-coated, the presentinvention provides that all of these parts are so coated without seams.Therefore, all of the visible parts of the frame including the recessedor unrecessed edge portions are more resistant to wear and easilycleaned. Also, since the coating according to the invention consists ofa thermosetting sheet plastic which is molded under heat and pressureupon the frame or its parts, it combines intimately or even integrallywith the frame since the latter also contains a thermosetting plastic.It is quite obvious that such a plastic coating will adhere to its base,the molded frame, much more securely and permanently than a sheet ofplastic which is merely glued to its base, namely, a solid-wood frame.

The above-mentioned features and advantages of the present inventionwill become further apparent from the following description thereofwhich is to be read with reference to the accompanying drawings of twodifferent embodiments thereof, in which FIGURE 1 shows a cross sectionwhich is taken along line 11 of FIGURE 2 and shows a compound door withrecessed outer edges and an internal structure of a corrugated shape;

FIGURE 2 shows a plan view of the same door;

FIGURE 3 shows a cross section which is taken along line 3-3 of FIGURE 4of a compound door with plane outer edges and an internal structure of ahoneycomb shape; while FIGURE 4 shows a plan view of the door accordingto FIGURE 3.

As illustrated in FIGURES l and 2 of the drawings, the compound dooraccording to the invention consists of a molded outer frame 1 which isprovided with recesses 2 in its lateral outer edges and with recesses 3for receiving the paneling 4 upon which, if desired, also a layer ofsheet plastic 5 may be molded or glued. According to the invention, theinner edges 6 of the recesses 3 are undercut and the outer edges of thepaneling are similarly beveled so as to fit tightly into the undercutedges 6. The space which is surrounded by the door frame 1 is bridged byan internal structure 7 which consists of a continuous molded web of thesame material of which the frame itself is made, namely, of a mixture ofa comminuted organic fibrous material, for example, wood chips, and athermosetting plastic. Although this internal structure 7 may be moldedto its desired shape in an operation separate from the operation ofmolding the frame 1, it is preferable to produce both parts, the frameand the internal structure, in one molding operation so that the twoparts are integrally connected to each other. The entire visible partsof the frame from one edge 6 to the other edge 6 are coated by acontinuous layer 8 of a thermosetting sheet plastic orplastic-impregnated material which is molded thereon without seams.

' Whereas the entire door frame 1 including the interior door structure7 according to FIGURES 1 and 2 consists of one integral piece in whicheven the corners 9 of the different sides of the frame are integrallyconnected without joints, FIGURES 3 and 4 show a modification of theinvention, in which only two opposite frame members 10 are moldedintegrally with the interior structure 11, while the two other framemembers 12 are separately molded, and then connected to the frame member10 by mitered joints 13. The beveled edges for these mitered joints 13may either be produced by molding or they may be cut in the conventionalmanner. Since the interior structure 11 is sufiiciently secured to theframe by being molded to the two opposite frame members 10 andsubsequently also to all frame members 10 and 12 by being glued to thepanels 14, it is not necessary also to secure the interior structure 11directly to the frame members 12. This embodiment of the invention hasthe advantage that it permits a mass production of doors of differentlengths or widths. The frame members 10 together with the interiorstructure 11 may then be made of a considerable length and may then bedivided to form the main bodies of several doors. The frame of each ofthese doors is then completed by securing the other frame members 12 tothe beveled ends of the frame members 10 to form the joints 13.Thereafter, the panels 14 which again may be plain or coated with sheetplastic 15 or the like are glued upon the end surfaces of the interiorstructure 11 and to the uncoated surfaces 16 of all frame members 10 and12 which again are preferably provided with undercut edges 17 into whichthe beveled edges of the coated or uncoated panels 14 are fitted. In theembodiment according to FIGURES 3 and 4, the outer edges 18 of the doorframe are plane and not recessed as in FIGURES 1 and 2, but they arelikewise coated with a continuous layer 19 of sheet plastic orplastic-impregnated material which reaches from one edge 17 to theother.

The interior structure may be of any desirable shape, as long as itscontact surfaces 20 or 21 are sufficiently large and sufiiciently closeto each other so that the panels 4 or 14 may be securely glued thereto.Thus, the interior structures may be made, for example, of a corrugatedshape with fiat outer contact surfaces 20, as shown in FIGURES 1 and 2,or of a honeycomb shape, as shown in FIGURES 3 and 4, which are likewiseprovided with flat contact surfaces 21.

Although my invention has been illustrated and described with referenceto the preferred embodiments thereof, I wish to have it understood thatit is in no way limited to the details of such embodiments, but iscapable of numerous modifications within the scope of the appendedclaims.

Having thus fully disclosed my invention, what I claim is:

1. A compound door, comprising: molded spaced apart frame members andintegrally connected molded internal structure spanning the spacebetween said frame members; said frame members and internal structurebeing molded from a mixture of comminuted organic fibrous material and athermosetting plastic; a recess molded into the opposite sides of eachof said frame members; paneling members adhered to each side of saidinternal structure and completely covering the opposite sides thereofand secured to said frame members by extending the lateral edges thereofinto said recesses; and a coating of sheet material containing athermosetting plastic molded to and completely covering all outer partsof said frame members up to the lateral edges of said paneling members.

2. A compound door in accordance with claim 1 wherein said recess thatis molded into the opposite sides of each of said frame members areprovided with a beveled surface and the lateral edges of said panelingmembers are provided with complementary beveled surfaces together withlongitudinal recesses formed in the lateral edge of each of said outerframe members.

3. A compound door, comprising: molded spaced apart frame members; amolded internal structure integrally connected with two opposite membersof said frame and being unsecured to the other tWo members of saidframe; the ends of said opposite members of said frame and the other twomembers of said frame being beveled and mitered together; said framemembers and said internal structure being molded from a mixture ofcomminuted organic fibrous material and a thermosetting plastic;recesses molded into the opposite sides of each of said frame members;paneling members adhered to each side of said internal structure andcompletely covering the opposite sides thereof and secured to said framemembers by extending the lateral edges thereof into said recesses; and acoating of sheet material containing a thermosetting plastic molded toand completely covering all outer parts of said frame members up to thelateral edges of said paneling members.

4. A compound door in accordance with claim 3 wherein said recesses areprovided with beveled surfaces and said lateral ends of said panelingmembers are provided with complementary beveled surfaces to interfitwithin said recesses.

References Cited by the Examiner UNITED STATES PATENTS 2,033,884 3/1936DavisOn 49400 2,090,480 8/ 1937 HaWley 52627 2,214,675 9/1940 Jensen52615 2,220,596 11/ 1950 Bernhardt 52-618 2,569,902 10/1951 Rienau et al52-456 2,593,050 4/1952 Paul et al. 52232 2,602,204 7/1952 Rizza 161-682,765,056 10/1956 Tyree 49399 2,931,746 4/1960 Wilson et a] 260869 XPrimary Examiner.

1. A COMPOUND DOOR, COMPRISING: MOLDED SPACED APART FRAME MEMBERS ANDINTEGRALLY CONNECTED MOLDED INTERNAL STRUCTURE SPANNING THE SPACEBETWEEN SAID FRAME MEMBERS; SAID FRAME MEMBERS AND INTERNAL STRUCTUREBEING MOLDED FROM A MIXTURE OF COMMINUTED ORGANIC FIBROUS MATERIAL AND ATHERMOSETTING PLASTIC; A RECESS MOLDED INTO THE OPPOSITE SIDES OF EACHSIDE OF SAID FRAME MEMBERS; PANELING MEMBERS ADHERED TO EACH SIDE OFSAID INTERNAL STRUCTURE AND COMPLETELY COVERING THE OPPOSITE SIDESTHEREOF AND SECURED TO SAID FRAME MEMBERS BY EXTENDING THE LATERAL EDGESTHEREOF INTO SAID RECESSES; AND A COATING OF SHEET MATERIAL CONTAINING ATHERMOSETTING PLASTIC MOLDED TO AND COMPLETELY COVERING ALL OUTER PARTSOF SAID FRAME MEMBERS UP TO THE LATERAL EDGES OF SAID PANELING MEMBERS.